Transmission Convergence Layer of NG-PON2 in VPIphotonics Tool

Passive optical networks are the most promising solution for access networks. The first standard provided only 155 Mbit/s but current networks work according to ITU-T G.984.3 with 2.5 Gbit/s in downstream. However, NG-PON2 offers up to 40 Gbit/s in downstream by 4 different wavelengths. This article deals with an implementation of transmission convergence layer in VPIphotonics. This tool is dedicated only for simulations of physical layer. The main aim is to present a simulation of physical layer for NG-PON2 in comparison with our implementation of transmission convergence layer and encapsulated frames according to ITU-T G.989.3. Our results confirm expanding the entire system reach with the real encapsulation method of 3 sublayers model and error correction mechanism. The 3 sublayers model can be easily extended to all passive optical networks simulations in VPIphotonics simulation tool

Development of high capacity transmission systems for future optical access networks

The cost-sensitivity of NG-PON2 and future optical access networks, employing wavelength division multiplexing (WDM) technology, may preclude the use of conventional LiNbO3-based intensity and I/Q modulators, as they are currently too expensive for use in the access domain. Cost-effective directly modulated lasers (DMLs) and electro-absorption modulated lasers (EMLs) will need to be employed and, thus, are expected to be integral components in the realisation of tunable laser sources for future optical access networks. The limitations of DMLs and EMLs as transmitters merit thorough investigation to further understand how these devices can be adapted or optimised for use as tunable laser sources in future optical access networks. In this thesis, the transmission performance of a directly modulated DFB laser (DML) and an externally modulated DFB laser monolithically integrated with an EAM (EML), are investigated. The performance of both devices under 12.5 Gbit/s NRZ-OOK modulation are evaluated for transmission over standard single-mode fibre (SSMF) in an IM/DD test-bed, with a view to further understanding the limitations of DMLs and EMLs in 10 Gbit/s IM/DD systems. Particular attention is given to the frequency chirp of the devices and how the chirp affects the performances of the devices for transmission over SSMF up to 50 km in length. Numerical models, which were developed in MATLAB, are utilised to simulate the characteristics and transmission performances of both the DML and EML. The latter half of this thesis is focused on the development of a self-seeded Fabry-Pérot (SS-FP) laser. The SS-FP laser is optimised and characterised, and the transmission performance of the directly modulated SS-FP laser over SSMF is evaluated in an IM/DD test-bed. Two intensity modulation (IM) formats are assessed, 12.5 Gbit/s NRZ-OOK and 12.5 Gbaud/s (25 Gbit/s) multilevel PAM-4, both IM formats are compatible with 10G class optical components and legacy PON deployments. The SS-FP laser holds potential for photonic integration, justifying its consideration as a candidate tunable laser source for next generation PONs and future optical access networks

OPEN PON: Seamless integration between 5G core and optical access networks

Nowadays business and users traffic demands are getting higher and higher, leaving optical fiber as the only reliable solution to meet its demands, and in access networks the dominating technology is Passive Optical Networks (PONs) where currently exists two main families of standards, the GPON (ITU-T standard) and the EPON (IEEE standard). In this work we tackle the latest version oof the GPON family, the NG-PON2. We analyse the Physical Media Dependent (PMD) and Transmission Convergence (TC) layer requirements and what is standardized in each one. We also have a look into the SDN paradigm, which decouples the control and data plane of network equipment concentrating the intellegence and complexity in a centralized controller, the OpenFlow protocol that is one of the main enablers of SDN, since it is the communication protocol betwwen the network devices and the SDN controller, and the SIEPON (IEEE 1904.1) standard which gives interoperability of the transport, service, and control planes in a multi-vendor environment. The introduction of the SDN paradigm in the xPON world is a hot research topic because it would add the total controllability of the PON infrastructure, and the coordination with the SDN-based control plane of the core networks. It would allow a centralized optimization of the different resources managed by the OLTs and a seamless coordination between OLTs and the core network. In the TC layer specifications, of NG-PON2, it is not standardized the bandwidth allocation of the system, we set ourselves to create a simple Dynamic Bandwidth Allocation (DBA) algorithm that would optimize the use of channels and wavelengths. Taking into account the NG-PON2 technology and all its features, the emerging trend to extend SDN to the optical access networks, the multi-vendor adaptation provided by the SIEPON stantdard, and the need to have a platform to develop and test DBA scheduling algorithms made that thecreation and deployment of a fully SIEPON-SDN-NG-PON2 emulation environment became the main goal of this work. To create this environment we employed the use of MikroTiks, where OpenWRT was installed as well as a set of packages that menabled the behaviour of a CPqD switch (or ofsoftswitch13), and the use of Raspberry Pis which maintained its original OS and only required the installation of a sepecific set of tools. The results obtained were quite positive confirming the possibility of not only creating but also testing different DBA scheduling algorithms in the deployed environment and matching the results expected to our created algorithm

Adaptive modulation techniques for passive optical networks

Smart use of fiber networks to increase capacity to the hom

Next generation technologies for 100 Gb/s PON systems

The worldwide explosion of Internet traffic demand is driving the research for innovative solutions in many aspects of the telecommunication world. In access systems, passive optical networks (PONs) are becoming the preferred solution towards which most providers are migrating thanks to the unrivalled bandwidth they can offer. PON systems with a capacity of 100 Gb/s are envisioned as the solution to the dramatic increase in bandwidth and will be essential to support the future fixed and mobile broadband services. However, many challenging aspects have to be addressed in order to overcome the limitations imposed by the physical layer while meeting the economical requirements for mass deployment. In this thesis a comprehensive approach is taken in order to address the most compelling problems and investigate a series of solutions to the current capacity limitations of PONs. Advanced modulation formats are used to achieve bit-rate enhancement from 10 Gb/s to 25 Gb/s re-using the same optoelectronic devices in order to provide a 2.5x increase in transmission speed without resorting to a newer, more expensive generation of higher speed devices. The management of chromatic dispersion is also addressed in order to extend the reach of the networks beyond the standard 20 km using either electronic or optical based compensation strategies. Transmission of 25 Gb/s traffic over fibre lengths of 40 and 50 km is demonstrated confirming the suitability of the proposed technologies for extended reach networks which could greatly reduce the number of existing nodes and hence the capital and operational costs of PONs. Optical amplification strategies are also discussed as a means to improve the physical reach of the networks, both in terms of distance and number of customers. Raman amplifiers and semiconductor optical amplifiers are investigated in order to extend the reach of a PON upstream channel. The results demonstrate a reach of up to 50 km which is more than double the typical fibre length of 20 km adopted in deployed systems today. A number of customers, up to 512, was also demonstrated in a 20 km network, increased from the typical 32 or 64 users of most commercial networks